[veonik]

WiFi calling is multicast, I think, so your phone just basically broadcasts it to the network and every device will see it, though only your router will actually do anything with it.

There's examples of WiFi calling causing this type of issue, described as a packet storm. For example, here's a reddit post with similar symptoms you're describing. https://www.reddit.com/r/networking/comments/3g31mc/iphone_w...

[wasipwned]

This actually makes the most sense so far. I hadn't even considered the possibility of multicast. Let me see if I can dig in further.